Objective:

To explore the pathological basis of low-enhancement nodules of prostate cancer on contrast-enhanced ultrasound (CEUS)

and to study the correlation between low-enhancement nodules of prostate cancer and Gleason score.

Methods:

Forty-eight patients with abnormal external glands of the prostate identified by transrectal CEUS were chosen. They underwent trans

rectal ultrasound-guided biopsy to confirm the pathological diagnosis of prostate cancer. The patients were divided into highenhancement group (

n

=36) and low/heterogeneous enhancement group (

n

=12) according to the contrast enhancement pattern of prostate nodules. The CD34 immunohistochemistry method was used to compare the vascular density in prostate nodules between the two groups. The correlation between the intensity of contrast enhancement and vascular density in prostate nodules was explored.

Results:

In 48 prostate cancer cases

36 with high-enhancement nodules

9 with low-enhancement nodules

and 3 with heterogeneous enhancement nodules were found by CEUS. The proportion of blood vessel-rich cases in high-enhancement group was higher thanthat in low/heterogeneous enhancement group

and the difference was statistically significant (

P

=0.017). The proportion of patients with high Gleason score in high-enhancement group was higher than that in low/heterogeneous enhancement group

but the difference was not statistically significant (

P

=0.061). The vascular density in high Gleason score group was higher than that in low Gleason score group

and the difference was statistically significant (

P

=0.046). Some of low and heterogeneous nodules had less blood vessels

and some were rich in blood vessels. The low-enhancement nodules rich in blood vessels often had low degree of vascular development and most of the blood vessels were not open. Bleeding and necrosis were found in one case.

Conclusion:

On CEUS the high-enhancement nodules of prostate cancer have higher vascular density and Gleason score. The vascular density and Gleason score in low/heterogeneous enhancement nodules are different. Among low-enhancement nodules

some have less blood vessels

and some are rich in blood vessels. Low-enhancement nodules rich in blood vessels might be related to low degree of vascular development and less opened blood vessels.